Boring mill for air-pump cylinders



Aug. 7, 1923. v 1,404,000

W. HURST BORING MILL FOR AIR PUMP CYLINDERS Filed Jan.- 8, 1921' 2 sheets-sheet 1 Alb AMM @z I lid .9

Aug.. 7, 1923. 1,464,000

W. HURST BORING MILL FOR AIR PUMP CYLINDERS Filed Jan. 8. 1921 2 Sheets-Sheet 2 Patented Aug. 7, i923.

"latte BORING MILL FOR .AIR-PUEIP CYLINDERS.

Application filed January 8, 1921. Serial No. 435,780.

To aZZ whom it may concern.-

Be it known that I, WILFRED Hons'r, a citizen of the United States, residing at Norwood, county of Norfolk, State of Massachusetts, have invented a certain new and useful improvement in Boring Mills for Air-Pump Cylinders, of which the following is a specification, reference being had therein to the accompanying drawings.

As is well understood by those skilled in the art, air pump cylinders for locomotives and the like eventually become scored and worn and require to be rebored torestore them to proper working condition. Heretofore, thishas been done by placing the cylinder in a boring mill, the work being set up in accordance with ordinar machine shop practice. The setting up of the work is of necessity a slow process requiring considerable skill, particularly as it is necessary to have the bores of the two opposed cylinders forming a single air brake equipment in perfect alignment with each other, since other Wise the rod of the double-headed piston will bind. The actual work of boring a cylinder is also very great and occupies the time of expensive equipment.

Accordingly, my invention has for its object to provlde a machine which can be placed directly on the cylinder castmg and can be set up quickly and accurately and will perform the operation of boring the cylinder rapidly. I find that 111 actual practice, the boring machine embodying my invention enables one man to perform the operation of boring a cylinder in less than a quarter of an hour, so that with my machine he can do a former weeks Work in less than a day. The equipment is inexpensive and requires very little skill in its operation.

The invention will be. fully understood from the following description when taken in connection with the accompanying drawings, and the novel features thereof will be pointed out and clearly defined in the claims at the close of this specification.

In the drawings, Fig. 1 is a top plan view of the machine embodying my invention.

Fig. 2 is an elevation partly in section.

Referring now to the drawing? at A is shown a cylinder casting and at the neck forming one cylinder head and carrying the stuffing boxes for the piston rod. It will be understood, of course, that these form no part of my invention but, on the contrary,

the cylinder A is the work on which the machine operates. The upper end of the cylinder is faced oil at a in manufacture and this face is at right-angles with the aXis of the piston rod used with the cylinder. It will also be understood that the flange hot the cylinder is supplied with a series of holes-c by means of which the cylinder head (not shown) is secured to the cylinder under normal working conditions. I take ad vantage of these facts to assist in setting up the machine embodying my invention.

At 11 is shown a bedplate which is annular in form and has holes 12 adapted to register with the holes 0 in the flange of the cylinder .51. At 7? is shown a T head bolt by which the bed plate is secured to the flange of the cylinder. In the bed plate are also holes 7" in which are located heavy studs 13 tapped out on the upper end, as shown, to receive a cap screw 9 and washer let. The studs 13 are turned down at 12. to form a shoulder and these turned-down portions pass through holes 15 in a face plate 18 which supports the working instrumentalities of the machine. t will ,therefore be seen that the bedplate 11, studs 13 and face plate 16 form a frame for the machine which can be secured on to the end of the cylinder. The face plate 16 is supplied with four horizontal adjusting screws 17, these being placed apart so that by loosening one pair of adjacent screws and tightening the opposite pair of screws, the centre of the face plate can be adjusted in any direction relatively to the centre of the cylinder. in practice, the adjusting screws are made with line threads and the adjustment is made by alternately loosening and tightening the screws until the desired adjustment is obtained.

At 18 is shown a boring bar mounted in a main bearing 3 revolubly mounted in the face plate 16. The lower end 2' of the boring bar is of lesser diameter and is received with in a guide member 19 which is screwed onto the s'tuiling box 5. This guide member 19 se ves to steady the boring bar 18, reduces the strain to which it would otherwise be subjected and increases the accuracy of the work. The boring bar has four keyways which cooperate with keys 7:; carried by a cutter hcad20 to which a cutter 21 is secured by the capscrews 22. It will therefore be seen that the cutter head 20 will rotate with the boring bar 18 but may move vertically alt) 0n the boring bar to feed the tool in and out of the work.

At 23 is shown a feed screw which engages a feed nut 24 seured to the cutter head 20' by the screw 25. The upper end of the feed screw 23 passes through a bearing at in the main bearing 3 and carries a pinion 26. This pinion 26 meshes with a these devices are conveniently accessible in railroad machine shops. I

At 32 is a bracket supported on the face plate 16. This bracket carries a spring-op erated latch 33 which can be drawn back by a handle 34 against the resistance of a spring 30. The nose of the latch engages notches 36 in a latch plate 37 which is fast to the gear 27 on the top of the boring bar. At 40 is shown a second shank for engagement with the flexible shaft or motor not shown.

In the ordinary operation of the machine, the guide member 19 is placed on the stufting box and. then the machine is placed on the top of the cylinder, the end of the boring bar being inserted. in the guide member 19. The machine is then secured in place on the cylinder, as described, and the boring bar is carefully centered by the adjusting screws 17. Then the machine is started with the application of power to the shank 31.

At this time. the latch 33 engages one of the notches in the latch plate 37 and restrains the gear 27 from rotation. The rotation of the shank 31 turns the pinion 29 and this causes the gear 28, the boring bar 18, the cutter head 20 and tool 21 to revolve at a reduced rate of speed determined by the relative sizes of the gear and pinion. Since the gear 27 is held stationary by the notch plate 37 and latch 33 and the gear 26 which is on the upper end of the feed screw 23 is carried around the boring bar 18 by the movement of the boring bar, the feed screw 23 is caused to revolve and feed the cutter head 20 slowly down the boring bar, thereby giving the tool the necessary feed. It will, therefore, be seen that the pinions 26 and 27 have a planetary motion. The movement described continues until the cutter 21 reaches the bottom of the cylinder when the machine is stopped by the operator. The operator then withdraws the latch. from the notch plate 37 and connects the motor to the shank 4:0. He then starts the motor and this causes the gear 27 to drive the gear The machine embodying my invention is relatively light and therefore can be handled and placed on the cylinders very easily. In fact it is possible to bore out a cylinder without removing the same from the side of the boiler of the locomotive.

What I claim is 1. A machine of the character described having in combination a feed screw having a pinion fast thereon, a boring bar having a pinion mounted loosely thereon and engaging with said pinion, a cutter head slidably mounted on said boring bar, a spring-actuated latch which normally engages a latch member fast to said loose pinion and re strains it from rotation, said latch being releasable at the will of the operator, driving means connected with the boring bar which can be made operative at will to rotate the boring bar and feed screw to feed the cutter head to its work, and thereby rotate the feed screw while the said loose pinion is latched against rotation, said loose pinion. having a member which is adapted to be connected at will with driving mechanism, and which, when so connected and the latch is released and said first driving mechanism is disconnected, will rotate the feed screw in the reverse direction and move the cutter head backwards.

2. A machine of the character described having in combination a rotatable boring bar, a cutter head mounted thereon in such manner as to be rotatable therewith and slidable longitudinally thereon, a gear mounted on said boring bar, a member having driving connection with said gear, whereby said boring bar may be rotated, a loose pinion mounted on said boring bar, a feed screw having feeding engagement with said cutter head, a pinion mounted fast on said feed screw and engaging with said loose pinion on the borbar, a springactuated latch which normally engages alatch member fast to said loose pinion and rest-rains the loose pinion from rotating with the boring bar, so that the feed screw is caused to rotate on its axis as well as to revolve withthe boring bar and cause the feed of the cutter head, said latch being releasable at the will of the operator, a second driving shaft independent of the said first driving member and connected with said loose pinion, each of said driving members being adapted for connection and disconnection at will with driving mechanism, whereby, if at the end of the forward feed the driving connection with the first driving member is disconnected and the latch is released, and driving connection is made with the second driving member, the said feed screw will be given a reverse rotation and the cutter head will be caused to move backward without rotation thereof.

A machine of the character described having in combination a rotatable boring bar, a cutter head mounted thereon in such manner as to be rotatable therewith and slidable longitudinally thereof, a gear mounted on said boring bar, a shaft having driving connection with said gear, whereby said boring bar may be rotated, a loose pinion mounted on said boring bar, a feed screw having feeding engagement with said cutter head, a pinion mounted fast on said feed screw and engaging with said loose pinion on the boring bar, latch mechanism which normally rest-rains the loose pinion on the boring bar from rotating with the boring bar, so that the feed screw is caused to rotate on its axis as well as to revolve with the boring bar and cause the feed of the cutter head in a direction to feed the tool to the work, said latch mechanism being releasable at the will of the operator, a second driving shaft independent of said first driving shaft and having driving connection with said loose pinion on the boring bar, each of said driving shafts being adapted forconnection and disconnection with driving mechanism, so that one of said driving shafts may be made operative while the other is inoperative,

whereby if at the end of the forward feed the driving connect-ion with the first driving shaft is disconnected and the latch released, and driving connection 151 made with the second driving shaft, the said feed screw will be given a reverse movement and the cutter head will be caused to move backward with out rotation thereof.

t. A machineof the character described having a frame adapted to be secured to the head of a cylinder to be bored, a face plate forming a part of said frame, said plate be ing at a distance from the cylinder head and having a circular opening therein, a boring bar having a bearing member journalled in said plate, a cutter head slidably mounted on said boring bar, a feed screw journalled in said bearing and engaging said cutter head, driving means for the boring bar consisting of a train of gears located between the said plate and the cylinder to be bored, a pinion fast on the head of the feed screw and located on the side of said bearing opposite to said driving train, a pinion loose on the boring bar, a latch mounted on said frame and engaging the pinion on the boring bar to restrain it from rotation, a driving connection for the loose pinion and another driving connection extending through the frame for the train of gears driving the boring bar.

5. A machine of the character described having a frame adapted tov be secured tothe head of a cylinder to be bored, a face plate forming a part of said frame, said plate being at a distance from the cylinder head and having a circular opening therein, a boring bar having a bearing member journalled in plate, a cutter head slidably mounted on said boring bar, a feed screw journalled in said bearing and engaging said cutter head, driving means for the boring bar consisting ofa train of gears located between the said plate and the cylinder to be bored, a pinion fast on the head of the feed screw and located on the side of said bearing opposite V to said driving train, a pinion loose on the boring bar, a latch mounted on said frame and engaging the pinion on the boring bar to restrain it from rotation, a driving connection for the loose pinion and another wiLrnEn 'nunsr. 

